TRACK VARIATIONS

Wairarapa Times-Age, 26 November 1943, Page 4

TRACK VARIATIONS

THEIR CUMULATIVE EFFECT important questions put BY CHAIRMAN TO WITNESS AT RAILWAY INQUIRY (By Telegraph—Press Association.) WELLINGTON, This Day.

At the inquiry into the cause of the derailment of the 7.25 a.m. Upper HuttWellington train near Haywards on November 8, the chairman, Sir Francis Frazer, summed up to a witness, Mr H. ‘L. P. Smith, district engineer of the southern railways district of the North Island, a sequence of events which might have occurred as a result of the track variations of which witness had spoken. “I put it to you,” said Sir Francis, “we have a change in the cant of one inch in 16 feet at 42 to 48 tfeet in front of the point of derailment. We have a sharpening of the curve to 9.9 chains at 66 feet before the point of derailment, which is roughly equivalent to the length of an engine. We have also a pinching of the gauge to l-16in. slack at six feet before the point of derailment. We have the high-leg rail worn to a fairly sharp angle on its inner side, and we have some pumping of the sleepers. Now, assuming just a moderate degree of stiffness in the engine, is it not possible that, striking that sharp point in the curve, we would get a roll?” Witness: Yes.

Sir Francis then suggested to witness that with the engine in this state of roll and approaching the irregularidty of cant, there might be a release of pressure on the rail and the engine might receive a push to the right through coming up against the righthand rail. When to this was added the fact that just before the' point of derailment the slack was pinched to l-16in., would there not be some effect?

Witness said that he did not think the pinching would have any effect. He would not expect the wheels to be bearing on the low leg of the curve at that distance, but in view of a roll in the engine it might be possible that lateral pressure by the left-hand wheels might cause a thrust. Sir Francis: And if we add the stiffness of the engine arid the vertical movement of the sleepers, might that not cause the derailment? —I do not think those factors would cause derailment.

Adding all those factors together you Would not rule them out as contributing to the derailment? —No. You could conceive of no other possibility?—No. Sir Francis: It seems to me that we have got to reach a conclusion by the process of exclusion.